This application claims the priority of Austrian Patent Application, Serial No. GM 141/2000, filed Feb. 29, 2000, the subject matter of which is incorporated herein by reference.
The present invention relates, in general, to a ballast tamping machine.
This type of a track maintenance machine is provided for tamping ballast underneath a railroad track, and generally includes a machine frame supported on the track by undercarriages for mobility in an operating direction, and a tamping unit and a track lifting and lining unit.
European Patent No. 0 436 757 B1 describes a ballast tamping machine including a tamping unit and provided with a pipeline for transporting ballast and associated with the tamping unit. In this manner, new ballast can be discharged onto the track in the region of the tamping unit. Thus, in track sections where there is a deficiency of ballast, the ballast bed can be filled up, as required, in parallel with the tamping operation.
U.S. Pat. No. 5,611,403 or British Patent No. 2 270 943 B describe track maintenance machines having a suction nozzle for aspirating ballast from the track.
It would be desirable and advantageous to provide an improved ballast tamping machine to realize optimal tamping results even in track sections that exhibit unserviceable ballast conditions.
The present invention provides for a machine for tamping ballast underneath a railroad track, which comprises a machine frame extending in a longitudinal direction and supported on the track by undercarriages for mobility in an operating direction. A tamping unit is mounted on the machine frame, and a track lifting and lining unit cooperates with the tamping unit. A suction apparatus for aspirating ballast is provided on the machine frame and includes a suction line connected to a ballast suction nozzle which is associated with the tamping unit. Drives are provided for adjusting the ballast suction nozzle vertically and transversely to the longitudinal direction. A ballast plow is mounted on the machine frame, and a discharge chute is provided for ejecting ballast onto the track.
This special combination of working devices makes it possible in an advantageous way to remove and replace ballast which is unfit for use in tamping operations or for attaining durable tamping results. Unusable ballast can be substituted immediately prior to the tamping procedure. The new ballast can be distributed evenly across the track by means of the ballast plow and can subsequently be compacted immediately with the aid of the tamping unit in order to create a durable and permanent track position. Advantageously, the tamping machine can be employed without any restriction whatsoever also for operation in normal track sections where the prevailing ballast conditions are satisfactory.
According to another feature of the present invention, the discharge chute is positioned between the ballast suction nozzle and the ballast plow. According to yet another aspect, ballast hoppers are mounted on the machine frame, and a longitudinal conveyor belt extending in the longitudinal direction is arranged partly underneath the ballast hoppers and has an ejection end associated with the discharge chute.
According to another feature of the present invention, a transverse conveyor belt is mounted on the machine frame and extends perpendicular to the longitudinal direction, with the longitudinal conveyor belt including a second end, distanced from the ejection end, which is arranged above the transverse conveyor belt. A second discharge chute having a receiving opening may be provided above the transverse conveyor belt, and the suction line may comprise a discharge opening emptying into the receiving opening.
According to another feature of the present invention, at least two ballast hoppers may be provided, one following the other in the longitudinal direction, with each ballast hopper being associated with a respective closeable discharge opening of the suction line for filling the hopper.